Investors' Dread-Letter Day: 11/23

Call it Wall Street's other geopolitical driver, one played out not in Athens or Rome, but close to home in Washington.

As stock-market investors fret over sovereign-debt contagion in Europe, a Nov. 23 deadline for the U.S. Congress's so-called budget supercommittee is fast approaching. The committee is assigned to devise at least $1.2 trillion in deficit-reduction measures over 10 years, or else automatic cuts ordained by...